Typically, a base station of a mobile communication system may be divided into a base station body for processing transmit and receive signals, and an antenna apparatus having a plurality of radiating elements for transmitting and receiving radio signals. Generally, the base station body is installed lower on the ground and the antenna apparatus is installed in a high position such as a building rooftop or a tower, both being interconnected through a feeder cable or the like.
The current mobile communication environment not only presents the 2G (Generation), 3G and 4G LTE (Long Term Evolution) communications in commercial deployment but also prepares for the introduction of the next generation 5G system. Various compliant communication systems or communication operators and different countries accordingly have the respective varieties of coexisting frequency bands of a variety of mobile communication services while making the base station environment diverse. Thus, in order to embody efficient base station systems and reduce the cost for operating base stations, a multi-band base station is commercialized for allowing a single base station to operate a plurality of communication systems.
To embody a multi-band base station, some recent antenna apparatuses have a multi-band antenna structure wherein one or more antenna arrays are installed through a single reflector or respective reflectors in each service band pursuant to different communication standards. The antenna array may be configured of an array of a plurality of radiating elements. Further, the antenna apparatus may have such structures, along with the multi-band structure, as a MIMO (Multi Input Multi Output) structure for each band, or a beam-forming antenna structure with, for example, three or more antenna arrays arranged in the same band.
To embody a multi-band base station, the base station body is provided with signal processing devices for respective bands, which process transmit and receive signals compliant with different communication standards and their associated service bands.
In addition, the base station is recently applied with mechanisms capable of carrying out a beam tilting for the antenna apparatus and various other motion controls, in order to carry out services adaptive to various environments, while suppressing signal interference to the minimum, and to maximize the capacity of the service. For example, the antenna apparatus may include, along with a typical RET (Remote Electrical Tilt) device for providing a remotely controllable electronic downtilt angle adjustment, so called “ALD (Antenna Line Device)” which is devices to be controlled, such as an RAS (Remote Azimuth Steering) device whose azimuth steering adjustment is remotely controlled and an RAB (Remote Azimuth Beamwidth) device whose azimuth beamwidth is remotely controlled. An exemplary antenna with these devices may be found in Korean Patent Application Publication No. 10-2010-0122092, which was priorly filed by Amphenol Corporation (Title: MULTI-BEAM ANTENNA WITH MULTI-DEVICE CONTROL UNIT, Inventors: GIRARD, Gregory; SOULIE, Frank, et al., published Nov. 19, 2010).
In order to control the ALD such as the abovementioned RET device, RAS device and RAB device, recently proposed are communications standards such as an AISG (Antenna Interface Standards Group) v3.0 and communication methods using a 3GPP (3rd Generation Partnership Project) protocol. According to the AISG standard, communication devices are largely classified into primary stations and secondary stations. The primary station or a master station refers to an MCU or such transmitting unit for installation in band-specific signal processing apparatuses of the base station body, which transmits a control signal. The secondary station or a slave station, including a RET device and an ALD modem for installation in an antenna apparatus, receives a control signal to perform an operation corresponding to the control signal.
As such, the existing antenna apparatuses typically have a complicated structure including a multi-band antenna structure, and the fact that an ordinary base station antenna has a multi-sector structure (e.g., alpha, beta and gamma sectors) for dividing a relevant service range by multiple coverage sectors and providing services on a sector-by-sector basis further complicates their linkages and control structures, which is aggravated when each coverage sector employs, for example, a plurality of antenna apparatuses. Therefore, studies are underway to check, when installing base station antennas, the connection state of each antenna apparatus and normality/abnormality of the connection state on a sector-by-sector basis.